Decompose children inherit the root's literal workspace_path (#37172),
so every sibling of a worktree-kind root points at the SAME checkout.
_resolve_worktree_workspace's existing-checkout shortcut then reuses
that directory on whatever branch is currently checked out, ignoring
the task's own branch_name. Net effect: sibling workers — which can be
promoted and dispatched concurrently — run in one directory on the
first sibling's branch, with no lock. Work lands on the wrong task's
branch (provenance corruption) and concurrent siblings trample each
other's index/tree.
Fix, two layers:
- decompose_triage_task: worktree-kind children no longer inherit the
root's literal path; each child materializes its own
<repo>/.worktrees/<child-id> at dispatch (dir/scratch inheritance
unchanged — children legitimately share those).
- _resolve_worktree_workspace: when the requested path is an existing
checkout of a DIFFERENT branch, fall back to a fresh
<repo>/.worktrees/<task-id> instead of silently reusing it (heals
rows that already carry a shared path). Same-branch reuse and the
no-repo/own-path degenerate cases keep the legacy behaviour.
Tests: tests/hermes_cli/test_kanban_worktree_isolation.py (5); full
test_kanban_db.py + test_kanban_decompose_db.py suites pass unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Ahmad